1. Field of the Invention
The present invention relates to a charge indicator of a battery.
2. Description of the Related Art
As a charge indicator of a battery used for electric vehicles such as an electric car and a forklift and for electronic devices, ones implemented by a method of measuring discharged ampere-hour of the battery, by a method of measuring a terminal voltage of the battery during discharge and by a method of measuring specific gravity of electrolyte of the battery are known.
Among the aforementioned methods utilized for the charge indicator, the method of measuring the discharged ampere-hour of the battery has such a problem that actual residual capacity fluctuates depending on discharge rate of the battery. The method of measuring the terminal voltage of the battery during discharge also has such a problem that a conversion circuit has to be provided to indicate the terminal voltage by discharging a constant set current. Furthermore, the method of measuring the specific gravity of electrolyte of the battery has such a problem that a high-precision specific gravity meter has to be used. Accordingly, it is an object of the present invention to solve the aforementioned problems by providing a charge indicator of a battery which can indicate residual capacity corresponding to discharge rate of the battery.